View Compilation Error

0_0_25175296_5154.cpp: In function 'int main()':
0_0_25175296_5154.cpp:6:39: error: 'scanf' was not declared in this scope
     while(scanf("%lf%lf%lf",&a,&v1,&v2)==3)
                                       ^
0_0_25175296_5154.cpp:10:36: error: 'printf' was not declared in this scope
             printf("0.0000000000\n");
                                    ^
0_0_25175296_5154.cpp:15:32: error: 'printf' was not declared in this scope
             printf("Infinity\n");
                                ^
0_0_25175296_5154.cpp:20:30: error: 'printf' was not declared in this scope
         printf("%.10lf\n",ans);
                              ^
0_0_25175296_5154.cpp:21:5: error: expected '}' at end of input
     }
     ^